<?php
/**
 * CCaptcha class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CCaptcha renders a CAPTCHA image element.
 *
 * CCaptcha is used together with {@link CCaptchaAction} to provide {@link http://en.wikipedia.org/wiki/Captcha CAPTCHA}
 * - a way of preventing site spam.
 *
 * The image element rendered by CCaptcha will display a CAPTCHA image generated
 * by an action of class {@link CCaptchaAction} belonging to the current controller.
 * By default, the action ID should be 'captcha', which can be changed by setting {@link captchaAction}.
 *
 * CCaptcha may also render a button next to the CAPTCHA image. Clicking on the button
 * will change the CAPTCHA image to be a new one in an AJAX way.
 *
 * Since version 1.0.8, if {@link clickableImage} is set true, clicking on the CAPTCHA image
 * will refresh the CAPTCHA.
 *
 * A {@link CCaptchaValidator} may be used to validate that the user enters
 * a verification code matching the code displayed in the CAPTCHA image.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CCaptcha.php 3203 2011-05-05 14:08:06Z qiang.xue $
 * @package system.web.widgets.captcha
 * @since 1.0
 */
class CCaptcha extends CWidget
{
    /**
     * @var string the ID of the action that should provide CAPTCHA image. Defaults to 'captcha',
     * meaning the 'captcha' action of the current controller. This property may also
     * be in the format of 'ControllerID/ActionID'. Underneath, this property is used
     * by {@link CController::createUrl} to create the URL that would serve the CAPTCHA image.
     * The action has to be of {@link CCaptchaAction}.
     */
    public $captchaAction='captcha';
    /**
     * @var boolean whether to display a button next to the CAPTCHA image. Clicking on the button
     * will cause the CAPTCHA image to be changed to a new one. Defaults to true.
     */
    public $showRefreshButton=true;
    /**
     * @var boolean whether to allow clicking on the CAPTCHA image to refresh the CAPTCHA letters.
     * Defaults to false. Hint: you may want to set {@link showRefreshButton} to false if you set
     * this property to be true because they serve for the same purpose.
     * To enhance accessibility, you may set {@link imageOptions} to provide hints to end-users that
     * the image is clickable.
     * @since 1.0.8
     */
    public $clickableImage=false;
    /**
     * @var string the label for the refresh button. Defaults to 'Get a new code'.
     */
    public $buttonLabel;
    /**
     * @var string the type of the refresh button. This should be either 'link' or 'button'.
     * The former refers to hyperlink button while the latter a normal push button.
     * Defaults to 'link'.
     */
    public $buttonType='link';
    /**
     * @var array HTML attributes to be applied to the rendered image element.
     */
    public $imageOptions=array();
    /**
     * @var array HTML attributes to be applied to the rendered refresh button element.
     */
    public $buttonOptions=array();


    /**
     * Renders the widget.
     */
    public function run()
    {
        if(self::checkRequirements())
        {
            $this->renderImage();
            $this->registerClientScript();
        }
        else
        throw new CException(Yii::t('yii','GD and FreeType PHP extensions are required.'));
    }

    /**
     * Renders the CAPTCHA image.
     */
    protected function renderImage()
    {
        if(!isset($this->imageOptions['id']))
        $this->imageOptions['id']=$this->getId();

        $url=$this->getController()->createUrl($this->captchaAction,array('v'=>uniqid()));
        $alt=isset($this->imageOptions['alt'])?$this->imageOptions['alt']:'';
        echo CHtml::image($url,$alt,$this->imageOptions);
    }

    /**
     * Registers the needed client scripts.
     * @since 1.0.2
     */
    public function registerClientScript()
    {
        $cs=Yii::app()->clientScript;
        $id=$this->imageOptions['id'];
        $url=$this->getController()->createUrl($this->captchaAction,array(CCaptchaAction::REFRESH_GET_VAR=>true));

        $js="";
        if($this->showRefreshButton)
        {
            $cs->registerScript('Yii.CCaptcha#'.$id,'dummy');
            $label=$this->buttonLabel===null?Yii::t('yii','Get a new code'):$this->buttonLabel;
            $options=$this->buttonOptions;
            if(isset($options['id']))
            $buttonID=$options['id'];
            else
            $buttonID=$options['id']=$id.'_button';
            if($this->buttonType==='button')
            $html=CHtml::button($label, $options);
            else
            $html=CHtml::link($label, $url, $options);
            $js="jQuery('#$id').after(".CJSON::encode($html).");";
            $selector="#$buttonID";
        }

        if($this->clickableImage)
        $selector=isset($selector) ? "$selector, #$id" : "#$id";

        if(!isset($selector))
        return;

        $js.="
jQuery('$selector').live('click',function(){
	jQuery.ajax({
		url: ".CJSON::encode($url).",
		dataType: 'json',
		cache: false,
		success: function(data) {
			jQuery('#$id').attr('src', data['url']);
			jQuery('body').data('{$this->captchaAction}.hash', [data['hash1'], data['hash2']]);
		}
	});
	return false;
});
";
        $cs->registerScript('Yii.CCaptcha#'.$id,$js);
    }

    /**
     * Checks if GD with FreeType support is loaded.
     * @return boolean true if GD with FreeType support is loaded, otherwise false
     * @since 1.1.5
     */
    public static function checkRequirements()
    {
        if (extension_loaded('gd'))
        {
            $gdinfo=gd_info();
            if( $gdinfo['FreeType Support'])
            return true;
        }
        return false;
    }
}

